Alcohol consumption is the third leading cause of preventable morbidity and mortality in the United States, and one of the highest risk population subgroups for problem drinking and alcohol related consequences are homeless women. Samples of homeless women, have shown upwards of two-thirds have had alcohol or combined alcohol and drug use problems during the last year. Half or more of homeless women with substance abuse issues have been reported to have a mental health condition, primarily depression. In addition, there is evidence that problematic alcohol and drug use are associated with high risk sexual practices, poor overall health, lower life expectancy, difficulty exiting homelessness, and prolonged episodes of homelessness. Homeless women also represent a growing proportion of the overall homeless population, now representing one-third of the homeless, while homeless families have grown at a rate of 30% since 2007 when the US economic conditions began to worsen. There is a need for current research that documents the prevalence of risky alcohol and drug use and co-occurring mental health and health conditions among this growing and changing population and begins to identify effective approaches to improve services for these conditions. The proposed study will sample 750 women drawn from primary care clinics in 10 organizations that are members of the National Health Care for the Homeless (HCH) Practice Based Research Network (PBRN), located in 8 states (California, Illinois, Ohio, Massachusetts, Nebraska, New Hampshire, New York, and Texas). Conducting the study in primary health care settings will result in reaching a broader sample of unstably housed women than using street or shelter populations, as well as is consistent with NIAAA, HSRA, and HUD priorities to improve the understanding of, and integration of, substance abuse and mental health prevention and treatment, in health care settings. The study aims are: 1) Describe the prevalence and correlates of past year risky alcohol and drug use, and their co-mobidity with mental and physical health conditions, among homeless women receiving primary health care services in HCH programs; 2) Describe access to substance abuse treatment, among women in this sample with past year risky alcohol or drug use, including the rate and correlates of perceived barriers to, and motivation to seek, substance abuse treatment, and the acceptability and perceived helpfulness of having primary health care providers in HCH programs assist with these issues; and 3) Identify potentially innovative approaches to prevent and treat substance abuse and mental health problems among women who seek primary health care in HCH programs.